The present invention describes a reciprocating engine with rocker valve gear according to the preamble of the independent claims. By way of example, the invention will be explained in more detail with reference to a 2-cylinder in-line engine, but it applies to reciprocating engines having any desired number of cylinders.
Engines having different kinds of valve gears are known in the art, e.g. according to FIG. 1, which schematically shows four different valve gears as described in the book Kraftfahrtechnisches Taschenbuch Bosch, published by VDI-Verlag, 19th edition, for example. One possible embodiment is the rocker valve gear shown in FIG. 1, drawing 3. Today, this kind of valve gear is used especially in engines where low friction and a low construction height are primary requirement s. The drawbacks of this design are substantially greater complications in machining and assembly of the valve gear, costly maintenance, and an increased space consumption in the longitudinal direction of the cylinders.
U.S. Pat. No. 5,605,077 discloses a reciprocating engine where the diameter of the bearings receiving the camshaft increases in the mounting direction, so as to facilitate the insertion of the camshaft. However, the precise machining of these bearing holes with different diameters is very costly. The reference also discloses that the rockers are supported at the same bearing locations, the bearings being enlarged at the locations of the rocker bores. Due to the fact that the rocker bores are disposed in the cylinder block, the assembly of the rockers can only take place in the cylinder head.
On the background of this prior art, it is the object of the present invention to eliminate the drawbacks of anterior rocker valve gears with respect to substantially greater complications in machining and assembly of the camshaft and of the rockers, costly maintenance, and increased space consumption in the longitudinal direction of the cylinders. An engine with rocker valve gear of this kind is defined in the independent claims. Further advantages and embodiments are described in the dependent claims.